Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.
J Am Chem Soc. 2013 Jul 17;135(28):10258-61. doi: 10.1021/ja404208a. Epub 2013 Jul 3.
Rationally designed Ru-based catalysts for efficient Z-selective olefin metathesis are featured. The new complexes contain a dithiolate ligand and can be accessed in a single step from commercially available precursors in 68-82% yield. High efficiency and exceptional Z selectivity (93:7 to >98:2 Z:E) were achieved in ring-opening metathesis polymerization (ROMP) and ring-opening/cross-metathesis (ROCM) processes; the transformations typically proceed at 22 °C and are operationally simple to perform. Complete conversion was observed with catalyst loadings as low as 0.002 mol %, and turnover numbers of up to 43,000 were achieved without rigorous substrate purification or deoxygenation protocols. X-ray data and density functional theory computations provide support for key design features and shed light on mechanistic attributes.
设计合理的钌基催化剂可高效实现 Z-选择性烯烃复分解。新型配合物含有二硫醇配体，可由商业上易得的前体制备，收率为 68-82%。在开环复分解聚合（ROMP）和开环/交叉复分解（ROCM）过程中，表现出高活性和优异的 Z-选择性（93:7 至>98:2 Z:E）；这些转化通常在 22°C 下进行，操作简单。催化剂负载量低至 0.002 mol%时即可实现完全转化，无需严格的底物纯化或脱氧程序，周转数最高可达 43000。X 射线数据和密度泛函理论计算为关键设计特征提供了支持，并阐明了其反应机理。
